Acrylonitrile-vinyl pyridine copolymer solutions



United States Patent ACRYLONITRHJE VINYL PYRIDINE .,COPOLYMER SOLUTIONS Ralph Gardner Beaman, Bulfalo, N. Y., as'signor toE. I. du Pont de N emours aa Company, Wilmington, Del., a corporation of Delaware No Drawing. Application August 9, 1949, SerialN0..109,404

6 Claims. (Cl. 260-302) This invention, relates to new compositions ;of matter and shaped articles produced therefrom. "More particularly, this invention relates to organic solvent solutions of acrylonitrile copolymers, i. e., copolymers and interpolymersof acrylonitrile in which at--least 85% and up to 95% by weight of the polymer is acrylonitrile and to the production of shaped articles from said solutions of said polymers.

Copolymers and interpolymers of acrylonitrile with other polymerizable substances, for example, vinyl. or acrylic compounds, in which at least 85% and ppm-95% by weight of the polymer is acrylonitrile, have been known for some time;;-a 11d recognized as possessing desirable physicaltand Chfimical properties including toughness and insolubility in and insensitivity to-common organic solvents such asmethyl-.or1ethyl alcohol, .acetone,

ethyl ether, ethylacetate, hydrocarbon solvents, chlori- -*nated hydrocarbons andrthe: like.

Because .of these facts, numerous attempts haveubeen.madexto fornr these polymeric materials. into yarns; films-t and other shaped articles.

:A number of solvents have been found :for ,polyacrylonitriles was exemplified ,in vU. -S. Patents 2,404,714- 2,404,727. However, in striving for thezproduction .of high quality products, such :as a1high quality ryarnyit has been found that many of'ther'known solventssdiavexdisadvantages even though they are-effective tandqzuseful solvents. For example, the use of dimethyl formamide, which is an excellent and useful solvent, leads, in dry spinning techniques, to the .production'of coloredlarticles and means, such as stabilizing or; bleaching, .are required to producearticles free from undesirablecolor. :Sim-

. ilarly, such a solvent as N,Nedimethylmethoxyacetamide is eXPensive and somewhat higher :boilingithan isudesi-red for economic .dry spinning procedures.

It is, therefore an object of ;:this inventionvatordissolve a copolymeror interpolyrnenof acrylonitrileingzwhich at least 85 and up to 95% .by. weightypf-it-heupolymeris :acrylonitrile in a solventuwhichtdoestnot react ;,with or decompose or discolor the polymer andv-whichrmayybe substantially completely removed. ;at. .relativelyqlow temperatures from the structuresnformed.fofvsuch.azsolution.

It is another object of -;this:invention .to :produce a solution of a copolymer orinterpolymer ofacrylonitrile in which at least-85%,, and.a1p=tox9-5s%:.byz:weight of the polymer is acrylonitrile in a solvent ..-.which idoes-not react with or decompose or discolor the polymer, the solution beingsuitable forithe formationof commercially useful, void free articlesv of acrylonitri-le polymers, for example yarns which are suitable,as textile yarns, and

wfilmswhich are suitable as wrapping tissues.

It is another object of this invention to produce a solution of a copolymer or interpolymer of ,a crylonitrile ...pontai ning 85% to"95'% by weight of, ,acrylo 'tri volatile grganic solvent which solution is stab ;:shaped articles and polymers. of acrylonitrile in which at least 1 85 and vup 'ito' 95:%1-;by .weightof the polymer is acrylonitrile.

-,acetyl pipe'ridine. stirring and "then cast on a smoothglass plate. The

';tubes,-.straws,artificial horsehair, bristles-and ribbons,- or whenhighly concentrated, for use inthemanufacturetof molded articles.

.It is .a stillfurther ,object .of this invention to-produce structures of copolymers or interit is still another, objectwofthis invention to.produce a .shaped article or structure .of ,copolymersor interpolymers mof acrylonitrile in whichatleast 85 and up to 95%. by

weight of thepolymer-is acrylonitrile,-:for example,t a

yarn, film, tube, bristle or the like which is tough, flexible,

tenacious and free from .voids.

Other objects of the ;inventionwill appearhereinafter. The objects ;,of this invention areaccomplished in generaL-by-dissolving copolymers ,or interpolymers of tac yl'onitrile conta ngt85 to 95 by. w ig t- .of acrylonitrile in h a sol en selected :from the --Neme by -Nr t yla etam wa ,N-dime hy p opio group consisting of am de n c yl p p t dine- T .z oll w ngze amm h h t artssprqp en a p t gc a e y :W i stra app ations of h p incipl of theimen ig EXAMPL flienipartssofta -95/5 ,-.copolym cr .of, acrylonitrile with v; 21V;1;I1'Y1 py din w sv lurrie t: room temperature -.:in 50 a s;otNaa tylpiperidine- Ihe mixture washeated h' s irring: t pro ce cle v eavy wis ou olution :ln h s m way, a s l t on-w EXAMPLE LII Ten parts of a 95/5 copolymer of acrylonitrile with styrene-was slurried atroom temperature in 100 parts of The--mixture was heated with polymer was precipitated: andsolvent removed by was1h- -i ng with water tohleave a'film. In the same-way, .a film -was obtainedusing. aI 90/"l0 copolymer of 'acrylonitrile wit-h methacrylonitrile.

- dine (pentamet-hyleneimine) invention are excellent-solvents for =t-he-acr-ylonitrile co- .EXAMPLE III 5 Fifteen parts of 2190/10 copolymer of acrylonitrile -with isobutylene was slurried at room tempqature in .85 parts ,of, N,N-d imethyl,propionarnide. j The mixture was heated with stirring to produce a viscous solution. ,Inthe same way a solution wasobtained using a /5 copolymer of acrylon itrile with 2-vinyl pyridine.

. Eifit en parts ofa fii icopp ymertof q ylqnitril -wi h This was poured, on a smooth removed by heating at C.

,to leave a clear. tough'film. In the same,,way, a film was obtained "usinga9S-/5 copolymer of acrylonitrile with methacrylic acid.

"The solvents of this invention are amides and 'specifically are amides with secondary amines. The secondary aminesare, 'methylethylamine, dimethylamine and piperi- While the solvents of this polymers, they are not solvents for the homopolymer.

'Ihe copolymers of acrylonitrile' for-use-in this inven- The compositions Jing' case.

acrylonitrile copolymers containing to195% acrylonitrile are decidedly enhanced by this intion can be prepared in any suitable manner such as those methods disclosed in U. S. Patent 2,160,054 or in U. S. Patents 2,404,714--2,404,727. The invention comprehends dissolving of acrylonitrile copolymers and interpolymers formed by polymerizing acrylonitrile with other polymerizable substances such as, for example, compounds containing 1 or more ethylenic linkages which may include styrene, dimethyl itaconate, methyl vinyl ketone, ethyl vinyl sulfone, methacrylonitrile, acrylic acid, vinyl pyridines, such as 2-vinylpyridine, vinyl acetate, vinyl chloride, isobutylene and butadiene. The solvents of this invention are eminently satisfactory for use with those copolymers which contain a large amount of acrylonitrile,

. for example, polymers that contain in the polymer molecule from 85% to 95 by weight of acrylonitrile. The solvent may be used in forming useful compositions with polymers having an average molecule weight between 15,000 and 250,000 as determined by viscosity data using the Staudinger equation. Such polymers are generally used in the manufacture of yarns and filaments. Generally, polymers having a molecular weight between 40,000 and 150,000 are preferred.

The above described solutions of the acrylonitrile copolymers may be shaped in the form of filaments, yarns,

films, tubes and like structures by apparatus and processes generally known in the art, the detailed operating conditions being suitably modified. The solutions are stable at room temperature and at elevated temperatures and may be used in producing shaped articles by extruding these solutions into an evaporative or coagulating medium.

Film formation is readily achieved by casting the solution '1 onto a smooth surface such as an endless steel band under the smoothing action of a doctor knife. The solvent may be removed either by the dry or evaporative method or by the wet method which utilizes a liquid coagulating H bath. Similarly, the solutions may be used in the manufacture of moulded articles or as lacquer or coating compositions, these being especially useful in the coating of wire and electrical parts where high chemical and electrical resistance is important.

In the preparation of shaped articles, solutions having a viscosity of from about 25 to 750 poises are preferred.

In addition to acting as solvents the solvents of this invention can also be used as plasticizing agents when present in small amounts. Non-solvent softeners such as glycerol may also be incorporated.

In preparing the compositions of this invention small amounts of the solvent may be used, as, for example, 40% to to produce compositions suitable for melt spinning. Smaller amounts, such as 5% to 40% or more, may p be employed to produce compositions useful in obtaining molded articles. In producing solutions for dry spinning or Wet spinning the amount of solvent ranges preferably from to The provision of the novel solvents of this invention is highly advantageous in that better slurry of the polymer at room temperature is obtained than heretofore possible with known solvents. This eliminates the necessity for heat treating the polymer to harden it in order to get improved slurrying so that rapid solution is possible. The stability of the solvents of this invention is sufliciently great in regard to color formation brought about by metal salts or by the development of impurities in the solvent at elevated temperatures to permit their use in the various spinning techniques. The solvents of this invention are higher boiling and permit higher spinning speeds in melt spinning than such a solvent as N,N-dimethylformamide. of this invention may be used in melt spinning following the procedure outlined in my copend- The possibilities for the commercialization of at least 85% and up vention.

duce the following:

4 Outdoor uses Auto tops Balloon fabric Belts for combines Fire hose covers Horse harness Life belts and preservers Mosquito netting Rainwear Outdoor sewing thread Sporting equipment Rubber covered Conveyor belt It was not expected that the solvents of this invention would be solvents in view of U. S. 2,404,714 which pointed out that a certain carbon to nitrogen ratio was essential. The solvents of this invention do not have the stated ratio. Further, related compounds are inefiective. For example, N,N-diethylacetamide is a non-solvent. The polymers of this invention possessing the aforesaid properties not possessed by other polymers require specific, unusual solvents.

Any departure from the procedure described herein which conforms to the principles of the invention is in tended to be included within the scope of the claims below.

I claim:

1. A new composition of matter comprising a copolyrner of acrylonitrile and a vinyl pyridine, containing in the polymer molecule 85% to by weight of acrylonitrile and correspondingly 5% to 15% of a vinyl pyridine dissolved in a solvent selected from the group consisting of N-methyl-N-ethylacetamide, N,N-dimethylpropionarnide and N-acetyl piperidine.

2. The composition of claim 1 in which the solvent is N-methyl-N-ethylacetamide.

3. The composition of claim 1 in which the vinyl pyridine is 2-vinylpyridine.

4. The composition of claim 3 in which the solvent is N-methyl-N-ethylacetamide.

5. The composition of claim 3 in which the solvent is N,N-dimethyl propionarnide.

6. The composition of claim 3 in which the solvent is N-acetyl piperidine.

Coated diaphragms References Cited in the file of this patent UNITED STATES PATENTS 1,986,854 Reid Jan. 8, 1935 2,404,714 Latham July 23, 1946 2,503,245 Coover Apr. 11, 1950 2,531,407 DAlelio Nov. 28, 1950 2,583,327 DAlelio Jan. 22, 1952 2,687,393 Trementozzi Aug. 24, 1954 

1. A NEW COMPOSITION OF MATTER COMPRISING A COPOLYMER OF ACRYLONITRILE AND A VINYL PYRIDINE, CONTAINING IN THE POLYMER MOLECULE 85% TO 95% BY WEIGHT OF ACRYLONITRILE AND CORRESPONDINGLY 5% TO 15% OF A VINYL PYRIDINE DISSOLVED IN A SOLVENT SELECTED FROM THE GROUP CONSISTING OF N-METHYL-N-ETHYLACETAMIDE, N,N-DIMETHYLPROPIONAMIDE AND N-ACETYL PIPERIDINE. 